In marine lighting applications, typically when using conventional lighting, such as that of halogen, incandescent, or fluorescent light sources, in order to achieve two different colors of light at the same location (i.e. a helm area) two different light fixtures are usually needed. In this case, either two fixtures are arranged side by side, one being a fixture having a white light with a color filter, such as a red filter, the other being a single fixture having a white light and possibly including a color filter. The addition of a color filter is, however, disadvantageous as luminaire efficacy is significantly reduced due to the fact that when red light that required (for example), only the red light is permitted to pass through the filter, the other colors being absorbed and therefore energy wasted.
In the case whereas a single fixture is used and yet two colors of light are desired, a further problem is that the filter must be changed when it is necessary to change from white to red light, thus in the case of having multiple fixtures installed within a single installation, for example six (6) fixtures within a helm area, all six fixtures would require filters to be installed.
There are several advantages of having the capacity to produce two or more colors within the same fixture as compared to having two fixtures, installed side by side. These advantages include a reduction in installation time (i.e. 1 fixture is required to be installed instead of two), wiring requirements, and the number of mounting holes that are required to be bored into the mounting surface. In addition, as more and more of today's lighting applications are becoming more streamlined, a single light fixture achieving the function of what would be traditionally two light fixtures, helps reduce clutter and better streamline the installation. Furthermore, as lighting becomes more and more a style/image and consumers look for options in how for example, their boat is illuminated at dockside, having the option of multiple colors within a fixture allow the user the option to have a practical lighting color for general operation (i.e. white light), but also have the option to change the lighting color on the entire vessel to for example blue, a color considered more aesthetic than functional due to the eye's poor response to the blue wavelength. While in traditional applications two colors of light (two separate lighting fixtures) may have been used in a helm area, through the use of the present invention, any location with a light source can now offer multiple colors. A control system which enables an operator to switch between the different colors, is therefore still wanting.
One arrangement which has been proposed in connection with the above need is disclosed in U.S. Pat. No. 6,967,448 to Morgan et al. This patent discloses the use of a remote user interface to provide control signals for controlling LED lights contained within a light source without having to use color filters. External signals are provided to a controller associated with the light source so the radiation (i.e. the light color) output by the light source is controlled.
In Morgan, individual LEDs or groups of the same color LEDs are coupled to independently controllable output ports of the controller associated with the light source. The controller is configured to modify one or more variable parameters of one or more illumination programs based on interruptions in the power signal. Morgan discloses a variable color radiation output from the LEDs based on the particular illumination program selected.
One drawback associated with the use an arrangement such as disclosed in Morgan et al. when it is used in a general lighting application, is wiring/circuitry/programming complexity and expense. That is to say, multiple controllers are required one per LED channel such that each LED controller may be controlled or dimmed in order to create the intended color mixing effect.
Another drawback associated with the above type of arrangement is that it is not possible to connect a high brightness LED directly to a microcontroller output when LEDs requiring high currents are used as a light source.
Further, in the case of a marine installation, for example, as a battery system is often used to power the lights, input voltages can fluctuate, in some cases as much as +/−3VDC.
In the case of general illumination, an LED based product will require regulation in order to maintain continuous light output and longevity over this full range. Other expenses required in the event that a color mixing system include a microcontroller with multiple PWM outputs. However, most small/inexpensive microcontrollers are not well equipped to trigger color control programs of the nature envisaged in arrangements such as disclosed in the above mentioned Morgan et al. patent.
Internal to the color mixing fixture, the device requires the generation of such signals another expensive device on the system, most likely being microcontroller based in order to send accurate pulses required by the microcontroller in Morgan such that the signal may be accurately interpreted and the proper program executed.
In other configurations, LED fixtures have been created with two or more colors of light within the same fixture however in the case of these fixtures, while the LEDs may include a common ground, each separate color requires an individual positive input, thus in the case of a two color fixture, there would be two positive wires and a common ground, thus in this case, this light could not be used as a direct retrofit for a conventional light unless additional wiring is run to the light location. Furthermore, in this scenario, each light color would require an independent LED driver in which case additional expense is added to each LED color, whereas in the present invention, one LED driver is shared for all light colors.
A low cost, retrofit compatible, LED lighting fixture having the capacity to selectively produce a series of different/multiple color lights is therefore still wanting in the art.